Power Transmission Apparatus for Working Vehicle

Abstract

A power transmission apparatus for a working vehicle has substantially symmetrically disposed first and second transaxles, each of which supports a single axle, and a working apparatus driving power take-off device including an input member. A gear casing is spanned between the first and second transaxles. A primary drive shaft is disposed in the gear casing so as to be drivingly connected to a prime mover. A traveling drive train is disposed in the gear casing so as to drivingly connect the primary drive shaft to the input shafts of the respective transaxles. A working apparatus drive train is disposed in the gear casing so as to drivingly connect the primary drive shaft to the input member of the working apparatus driving power take-off device.

1 . A power transmission apparatus for a working vehicle, comprising:
 substantially symmetrically disposed first and second transaxles, each of which supports a single axle;   a working apparatus driving power take-off device including an input member;   a gear casing spanned between the first and second transaxles;   a primary drive shaft disposed in the gear casing so as to be drivingly connected to a prime mover;   a traveling drive train disposed in the gear casing so as to drivingly connect the primary drive shaft to the input shafts of the respective first and second transaxles; and   a working apparatus drive train disposed in the gear casing so as to drivingly connect the primary drive shaft to the input member of the working apparatus driving power take-off device.   
   
   
       2 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the working apparatus driving power take-off device is disposed between the first and second transaxles in the axial direction of the axles. 
   
   
       3 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the input shafts of the transaxles are inserted into the gear casing, wherein the primary drive shaft is disposed at the middle between the input shafts of the transaxles, wherein a first drive train portion of the traveling drive train from the primary drive shaft to the input shaft of the first transaxle is a first gear train, wherein a second drive train portion of the traveling drive train from the primary drive shaft to the input shaft of the second transaxle is a second gear train, and wherein the first and second gear trains are disposed substantially symmetrically with respect to the primary drive shaft. 
   
   
       4 . The power transmission apparatus for a working vehicle according to  claim 3 , wherein the working apparatus drive train includes a gear train between the primary drive shaft and the input member of the working apparatus driving power take-off device. 
   
   
       5 . The power transmission apparatus for a working vehicle according to  claim 4 , wherein the gear train serving as the working apparatus drive train is disposed substantially perpendicularly to the first and second gear trains serving as the traveling drive train. 
   
   
       6 . The power transmission apparatus for a working vehicle according to  claim 3 , wherein the primary drive shaft serves as the input member of the working apparatus driving power take-off device. 
   
   
       7 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the input shaft of the first transaxle serves as the primary drive shaft, and wherein the drive train portion to the second transaxle is a gear train from the primary drive shaft to the input shaft of the second transaxle. 
   
   
       8 . The power transmission apparatus for a working vehicle according to  claim 7 , wherein the working apparatus drive train includes a gear train to the input member of the working apparatus driving power take-off device branched from an intermediate portion of the gear train from the primary drive shaft to the input shaft of the second transaxle. 
   
   
       9 . The power transmission apparatus for a working vehicle according to  claim 8 , wherein the gear train of the working apparatus drive train branched to the input member of the working apparatus driving power take-off device is disposed substantially perpendicularly to the gear train from the primary drive shaft to the input shaft of the second transaxle. 
   
   
       10 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the traveling drive train has a plurality of rotary shafts and at least one of the rotary shafts constituting the traveling drive train projects outward from the gear casing so as to be provided thereon with a cooling fan enabling cooling both of the first and second transaxles. 
   
   
       11 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the input shafts of the respective first and second transaxles penetrate the gear casing, and project outward from the gear casing so as to be provided thereon with respective cooling fans. 
   
   
       12 . The power transmission apparatus for a working vehicle according to  claim 1 , the working apparatus driving power take-off device including:
 a power take-off shaft; and   a clutch for selectively drivingly engaging or disengaging the input member of the working apparatus driving power take-off device to and from the power take-off shaft.   
   
   
       13 . The power transmission apparatus for a working vehicle according to  claim 12 , wherein the clutch is disposed inside the gear casing. 
   
   
       14 . The power transmission apparatus for a working vehicle according to  claim 12 , wherein the clutch is continuously connected to the outside of the gear casing. 
   
   
       15 . The power transmission apparatus for a working vehicle according to  claim 12 , wherein the working apparatus driving power take-off device includes a gear train interposed between the clutch and the power take-off shaft. 
   
   
       16 . The power transmission apparatus for a working vehicle according to  claim 15 , wherein the gear train of the working apparatus driving power take-off device interposed between the clutch and the power take-off shaft is disposed between the first and second transaxles. 
   
   
       17 . The power transmission apparatus for a working vehicle according to  claim 16 , wherein the gear train of the working apparatus driving power take-off device interposed between the clutch and the power take-off shaft is disposed substantially perpendicularly to the traveling drive train. 
   
   
       18 . The power transmission apparatus for a working vehicle according to  claim 12 , wherein a plurality of power take-off shafts serve as the power take-off shaft of the working apparatus driving power take-off device, and wherein a selector is disposed between the plurality of power take-off shafts at the downstream side of the clutch so as to selectively transmit power to the plurality of power take-off shafts. 
   
   
       19 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the integral assembly unit of the gear casing and the transaxles can be selectively mounted onto a vehicle frame whether the primary drive shaft is disposed vertically or horizontally, in correspondence to the output direction of the prime mover. 
   
   
       20 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein fluid can flow among the first and second transaxles and the gear casing. 
   
   
       21 . The power transmission apparatus for a working vehicle according to  claim 1 , wherein the gear casing is formed integrally with a housing having a pair of opposite portions constituting the respective first and second transaxles. 
   
   
       22 . The power transmission apparatus for a working vehicle according to  claim 21 , wherein the housing has a portion constituting the working apparatus driving power take-off device between the opposite portions constituting the respective first and second transaxles in the axial direction of the axles.